This invention relates generally to rate gyroscopes and, more particularly, to two degree of freedom rate gyroscopes.
As is known in the art, rate gyroscopes have been used in a variety of applications, such as in homing missile systems for stabilization of a seeker tracking system and for stabilization of the missile through an autopilot.
One type of rate gyroscope is a single degree of freedom rate gyroscope. Here a mass is adapted to rotate about a spin axis of the gyroscope. In response to an angular rate about a single axis of the gyroscope, the mass pivots about an axis of a precession. The axis of precession, the input axis and the spin axis are mutually orthogonal. It follows then that since such gyroscope measures angular rates about the single axis two separate single degree of freedom rate gyroscopes would be required in measuring pitch and yaw angular rates.
A second type of rate gyroscope is a two degree of freedom rate gyroscope. One such gyroscope includes a drive shaft having a precisely machined, flexible end portion. The mass is coupled to the flexible end portion of a motor drive shaft. The mass is rotated by the motor and is adapted to pivot about two orthogonal axes of precession in response to angular rates about two orthogonal input axes. While such arrangement is useful in some applications, it is relatively difficult to accurately produce the flexible end portion of the drive shaft and provide a relatively inexpensive accurate two degree of freedom rate gyroscope.